Lubricating structure for a wheel driving apparatus

ABSTRACT

A lubricating structure for a wheel driving apparatus in which a wheel hub (7) is rotatably supported by a wheel mounting body (1). An output side of a hydraulic motor (31) is attached to the mounting body and is coupled to a drive shaft (6) which is engageably inserted into a shaft bore (50) of the wheel mounting body. The drive shaft is coupled to the wheel hub via a reduction gear mechanism (10) and a clutch mechanism (11), and a braking mechanism (37) is mounted between the wheel hub and the wheel mounting body. The lubricating structure is characterized in that an annular space (51), formed between the shaft bore and the drive shaft, communicates via individual lubricable portions with a lubricant oil inlet (103) and a peripheral port (55). Also, the lubricant oil is supplied from the lubricant oil inlet and is discharged from the port.

TECHNICAL FIELD

The present invention relates to a structure for lubricating eachindividual part of a wheel driving apparatus provided with a brakingmechanism while coupling an output side of a hydraulic motor to a wheelvia a reduction gear mechanism and a clutch mechanism.

BACKGROUND ART

In a wheel driving apparatus provided with a reduction gear mechanism, aclutch mechanism and a braking mechanism, there arises a need to besupplied with a lubricant oil for the purposes of lubricating andcooling each individual part therein.

To this end, it is conceivable that use is made of a conduit forconnection to each of the decelerating mechanism, the clutch mechanismand the braking mechanism. This measure is, however, found to bedisadvantageous in that an excessive number of conduits are required anda space for those conduits needs to be excessively enlarged.

The present invention has been made to obviate the conventionalinconveniences mentioned above, and has an object of providing alubricating structure for a wheel driving apparatus whereby thoseindividual lubricable portions can be thoroughly lubricated and cooledonly with a reduced number of conduits.

SUMMARY OF THE INVENTION

In order to achieve the foregoing and other objects, there is providedin accordance with the present invention and in one form thereof, alubricating structure for a wheel driving apparatus in which a wheel hubon which a tire is mounted is rotatably supported by a wheel mountingbody. An output side of a hydraulic motor that is attached to the rotarymounting body is coupled to a drive shaft which is engageably insertedinto a shaft bore of the wheel mounting body. The drive shaft is coupledto the said wheel hub via a reduction gear mechanism and a clutchmechanism, and a braking mechanism is mounted between the wheel hub andthe wheel mounting body.

The lubricating structure is characterized in that an annular spaceformed between the shaft bore and the drive shaft is communicated viaindividual lubricable portions with a lubricant oil inlet and aperipheral port, respectively. The lubricant oil is supplied from thelubricant oil inlet and is discharged from the port.

With the structure so constructed, the lubricant oil introduced into theannular space between the drive shaft and the shaft bore will be caused,by the action of a centrifugal force, to flow through those individuallubricable portions into the port and will then be discharge from theport. Accordingly, those individual lubricable portions can bethoroughly lubricated and cooled only with a reduced number of conduits.

In this connection, it should be noted that it is preferable that theabove-mentioned lubricant oil inlet is formed in a cover having theafore-mentioned hydraulic motor attached thereto. Also, preferably, agear containing portion should be provided between the afore-mentionedlubricant oil inlet and the afore-mentioned annular space.

Further, it is typical that the afore-mentioned wheel hub is supportedby the afore-mentioned wheel mounting body via a bearing and that thisbearing is located between the afore-mentioned annular space and theafore-mentioned port.

It is also preferable that the afore-mentioned braking mechanism shouldbe positioned between the afore-mentioned annular space and theafore-mentioned port.

What is more, a discharging conduit should preferably be provided forconnection with the afore-mentioned port.

The present invention also provides, in another form thereof, alubricating structure for a wheel driving apparatus in which a wheel hubon which a tire is mounted is rotatably supported by a wheel mountingbody. An output side of a hydraulic motor that is attached to the rotarymounting body is coupled to a drive shaft which is engageably insertedinto a shaft bore of the wheel mounting body. The drive shaft is coupledto the wheel hub via a reduction gear mechanism and a clutch mechanism.And a braking mechanism is mounted between the wheel hub and the wheelmounting body.

The lubricating structure is characterized in that a first oil apertureis formed in a central side of the wheel mounting body, that the firstoil aperture is communicated via a rotary sealing portion with a secondoil aperture which is formed in the wheel hub, that the second oilaperture is communicated to a pressure receiving chamber of the clutchmechanism, that the rotary sealing portion is communicated with aperipheral port via the individual lubricable portions, and that aleakage oil from the rotary sealing portion is discharged from the portwhile a clutching purpose pressurized lubricant oil is supplied from thefirst oil aperture.

With the structure so constructed, because a portion of the clutchingpurpose pressurized oil adapted for switching on and off the clutchmechanism is leaked from the rotary sealing portion for passing throughthe individual lubricable portions to flow into the port and then toflow out from the port, only a reduced number of the conduits can berequired to thoroughly lubricate and cool those individual lubricableportions.

In this connection, it is preferable that the wheel hub should besupported by the afore-mentioned wheel mounting body via a bearing andthat this bearing should be located between the afore-mentioned rotarysealing portion and the afore-mentioned port.

In addition, the afore-mentioned braking mechanism should preferably bepositioned between the afore-mentioned rotary sealing portion and theafore-mentioned port.

What is more, a discharging conduit should preferably be provided forconnection with the afore-mentioned port.

The present invention further provides, in yet another form thereof, alubricating structure for a wheel driving apparatus in which a wheel hubon which a tire is mounted is rotatably supported by a wheel mountingbody. An output side of a hydraulic motor that is attached to the rotarymounting body is coupled to a drive shaft which is engageably insertedinto a shaft bore of the wheel mounting body. The said drive shaft iscoupled to the wheel hub via a reduction gear mechanism and a clutchmechanism, and a braking mechanism is mounted between the wheel hub andthe wheel mounting body.

The lubricating structure is characterized in that an annular spaceformed between the shaft bore and the drive shaft is communicated viaindividual lubricable portions with a lubricant oil inlet and aperipheral port, respectively, and that the lubricant oil is suppliedfrom the lubricant oil inlet and is discharged from the port.

Also a first oil aperture is formed in a central side of the wheelmounting body, that the first oil aperture is communicated via a rotarysealing portion with a second oil aperture which is formed in the wheelhub. The second oil aperture is communicated to a pressure receivingchamber of the clutch mechanism. The rotary sealing portion iscommunicated with the port via the individual lubricable portions. Also,a leakage oil from the rotary sealing portion is discharged from theport while a clutching purpose pressurized lubricant oil is suppliedfrom the first oil aperture.

In this connection, it is preferable that the wheel hub should besupported by the afore-mentioned wheel mounting body via a bearing andthat this bearing should be located between the afore-mentioned rotarysealing portion and the afore-mentioned port.

In addition, the afore-mentioned braking mechanism should preferably bepositioned between the afore-mentioned rotary sealing portion and theafore-mentioned port.

What is more, a discharging conduit should preferably be provided forconnection with the afore-mentioned port.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will better be understood from the followingdetailed description and the drawings attached hereto showing certainillustrative embodiments of the present invention. In this connection,it should be noted that such embodiments as illustrated in theaccompanying drawings are intended in no way to limit the presentinvention, but to facilitate an explanation and understanding thereof.

In the accompanying drawings:

FIG. 1 is a cross-sectional view illustrating a first embodiment of thelubricating structure for a wheel driving apparatus according to thepresent invention;

FIG. 2 is a cross-sectional view illustrating a second embodiment of thelubricating structure for a wheel driving apparatus according to thepresent invention; and

FIG. 3 is an enlarged cross-sectional view of the collar portion in FIG.2.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a lubricating structure for a wheel driving apparatusaccording to the present invention will be described, first with respectto a first embodiment thereof with reference to FIG. 1.

As shown in FIG. 1, a wheel 2 is mounted on a wheel mounting body 1which is supported so as to be capable of rocking up and down through asuspension cylinder 3 on an automobile body not shown. The wheel 2 isthus made as capable of being steered leftwards and rightwards relativeto the mobile body.

The afore-mentioned wheel mounting body 1 comprises a mounting base 4and a cylindrical supporting shaft portion 5 which is directedleftwardly and rightwardly. A drive shaft 6 is rotatably inserted intoand supported by the supporting shaft portion 5. A wheel hub 7 isrotatably supported via a bearing 8 on the peripheral surfaces of thesupporting shaft portion 5. A tire 9 is mounted on the wheel hub 7 so asto construct the wheel 2. And, one end of the afore-mentioned driveshaft 6 and the wheel hub 7 are coupled together via a reduction gearmechanism 10 of a planetary gear type and a clutch mechanism 11.

The afore-mentioned reduction gear mechanism 10 comprises: an inputshaft 13 that is connected via a coupling 12 to the afore-mentioneddrive shaft 6; a first sun gear 14 that is integrally mounted on theinput shaft 13; a first planetary gear 15 that is threadedly engagedwith the first sun gear 14; a first carrier 16 that is arranged tosupport the first planetary gear 15; a fixed ring gear 17 that iscoupled in a spline engagement with an end portion of the supportingshaft portion 5 of the afore-mentioned wheel mounting body 1; a secondcarrier 18 that is coupled in a spline engagement with the fixed ringgear 17; a second planetary gear 20 that is pivotally supported on thesecond carrier 18; a second sun gear 19 that is rotatably supported bythe input shaft 13 and is threadedly engaged with the planetary gear 20;and a cylindrical drive body 21 that is rotatably supported in theafore-mentioned wheel hub 7. The afore-mentioned first and secondplanetary gears 15 and 20 are threadedly engaged respectively with afirst and a second inner tooth 22 and 23 formed in the cylindrical drivebody 21 while the first carrier 16 is threadedly engaged with the secondsun gear 19 so as to form a two gear ratios reduction gear mechanism.

In the afore-mentioned clutch mechanism 11, a drive clutch plate 25 anda follower clutch plate 26 are mounted in a spline engagementalternately on a cylindrical follower body 24 that is bolted to thewheel hub 7 and on the afore-mentioned cylindrical drive body 21 so thatthe follower clutch plate 26 may be urged to contact the drive clutchplate 25 by means of a piston 27. The piston 27 is ring shaped in orderto be engageably inserted into an annular recess 28 of the wheel hub 7,thereby forming a pressure receiving chamber 29. When the pressurereceiving chamber 29 is supplied with a pressurized oil, the piston 27will be extended to urge into contact the drive clutch plate 25 and thefollower clutch plate 26 with each other so as to transfer a rotation ofthe drive shaft 6 to the wheel hub 7. When the pressurized oil in thepressure receiving chamber 29 is being discharged, the piston 27 will beretracted so that the afore-mentioned drive clutch plate 25 and followerclutch plate 26 may be removed away from each other so as to makediscontinuous a reduction gear mechanism 10 that is mounted on the driveshaft 6 and the afore-mentioned wheel hub 7. When this discontinuouscondition is developed at the time of high speed traveling of themobile, the reduction gear mechanism 10 will not be rotated with anyrotation of the wheel 2. Thus, the various individual portions in thereduction gear mechanism can be prevented from any abnormal wear.

In the region of an end surface 30 which is opposite to the side of themounting base 4 of the afore-mentioned wheel mounting body 1, relativeto the wheel 2 there is disposed a hydraulic motor 31 whose motor body32 is secured to the end surface 30 by means of bolts 33. The hydraulicmotor 31 has its rotary axis 34 coupled to the drive shaft 6 via a firstgear 35 and a second gear 36.

More specifically, the wheel mounting body 1 is formed with a shaft bore50 by which the supporting shaft portion 5 and the mounting base 4 arepenetrated. The end surface 30 of the mounting base 4 is formed with arecess 100 whereas a cover 101 is bolted to form a gear containingportion 102 which is continuous with the shaft bore 50. The gearcontaining portion 102 is provided with the first gear 35 and the secondgear 36 whereas the cover 101 has the hydraulic motor body 32 securedthereto.

Also, a braking mechanism 37 is provided between the afore-mentionedsupporting shaft portion 5 and wheel hub 7. The braking mechanism 37 isprovided with one end plate 39 which is coupled by bolts 38 to anoutwardly oriented flange 20a of the supporting shaft portion 5. Theafore-mentioned one end plate 39 has a cylindrical body 40 attachedthereto which is in turn secured to the other end plate 44. A pluralityof braking disks 41 are mounted with alternate spline engagement to thecylindrical body 40 and the wheel hub 7, respectively. By operating apiston 42 with the pressurized oil in the oil chamber 43, the brakingdisks 41 are thrust into contact with the other end plate 44. Thus, thewheel hub 7 is braked by so thrusting into contact the braking disks 41with each other.

Next, the lubrication of the individual portions will be describedbelow.

The cover 101 for mounting the afore-mentioned motor body 32 thereon isformed with a lubricant oil inlet 103, which is open to the gearcontaining portion 102 of the wheel mounting body 1 and is communicatedwith an annular space 51 formed by the shaft bore 50 and the drive shaft6. This annular space 51 communicates with an annular space 53 betweenthe supporting shaft portion 5 and the wheel hub 7 via the oil aperture52 extending in a radial direction of the supporting shaft 5. Theannular space 53 communicates through the bearing 8 with a space 54between the wheel hub 7 and the one end plate 39. The space 54 in turncommunicates through between the braking disks 41 of the brakingmechanism 39 with a peripheral port 55, which is connected to thedischarging conduit 56. The afore-mentioned inlet 103 for the lubricantoil is connected to a lubricant oil supply conduit not shown.

With the structure so constructed, a lubricant oil introduced from thelubricant oil inlet 103 will flow into the annular space 51 from thegear containing portion 102. In this state, the first and second gears35 and 36, and a bearing 103 will be lubricated. Further, by the actionof a centrifugal force, the lubricant oil will flow through the oilaperture 52, the annular space 53, the space 54 and the gaps between thebraking disks 41 into the port 55 and then will flow out into adischarging conduit 56 from the port 55. The individual parts will thusbe thoroughly lubricated and cooled.

As has been set forth in the foregoing, the lubricant oil introducedinto the annular space 52 formed by the drive shaft 6 and the shaft bore50 will by the action of a centrifugal force, to flow through thoseindividual lubricable portions into the port 55 and will then bedischarge from the port 55 into the discharging conduit 56. Accordingly,those individual lubricable portions can be thoroughly lubricated andcooled with a reduced number of conduits.

Next, reference is made to a second embodiment of the present invention.

As shown in FIG. 2, the peripheral surface of the afore-mentionedsupporting shaft portion 5 is engaged with a first collar 60 whereas asecond collar 61 is engaged between the first collar 60 and the innersurface of the wheel hub 7. As shown in FIG. 3, the first collar 60 hasattached thereto a seal member 62 such as to seal the engagement portionbetween the first collar 60 and the second collar 61.

The afore-mentioned first and second collars 60 and 61 are formed withoil apertures 63 and 64, respectively. The oil aperture 63 of the firstcollar 60 communicates with an output side of a clutch valve not shownvia an oil aperture 65 of the wheel mounting body 1, whereas the oilaperture 64 of the second collar 61 communicates with the pressurereceiving chamber 29 of the afore-mentioned clutch mechanism 11 via anoil aperture 66 of the wheel hub 7. A portion of the pressurized oil forclutching purposes which is supplied under pressure from a clutch valvewill be leaked at the engagement portion between the first and secondcollars 60 and 61, that is, from the rotary sealing portion to flow intothe afore-mentioned annular space 53; then, by action of a centrifugalforce, to flow through and thereby lubricate various individual partssimilarly as mentioned above; and finally to flow out from theperipheral port 55 into the discharging conduit 56.

As has been set forth in the foregoing, there is hereby provided alubricating structure for a wheel driving apparatus in which a portionof the clutching purpose pressurized oil for switching on and off theclutch mechanism 11 is leaked from the rotary sealing portion so as toflow through various individual lubricable portions into the port 55 andthen to flow out from the port 55 into the discharging conduit 56.Accordingly, those lubricable portions can be thoroughly lubricated andcooled with a reduced number of conduits.

In connection with the above, it should also be noted that there may beconstructed, in accordance with the present invention, a lubricatingstructure that is provided with both aspects of the foregoing first andsecond embodiments thereof.

While the present invention has hereinbefore been described with respectto certain illustrative embodiments thereof, it will readily beappreciated by those skilled in the art to be obvious that manyalterations thereof, omissions therefrom and additions thereto can bemade without departing from the essence and the scope of the presentinvention. Accordingly, it should be understood that the presentinvention is not limited to the specific embodiments thereof set outabove, but includes all possible embodiments thereof that can be madewithin the scope with respect to the features specifically set forth inthe appended claims and encompasses all equivalents thereof.

INDUSTRIAL APPLICABILITIES

As has been described hereinbefore, it will be understood that alubricating structure for a wheel driving apparatus according to thepresent invention is extremely useful in the lubrication of variousparts in a wheel driving apparatus such as in a dump car.

I claim:
 1. A lubricating structure for a wheel driving apparatus, saidlubricating structure comprising:a wheel mounting body rotatablysupporting a wheel hub on which a tire can be mounted; a shaft boreformed in said wheel mounting body; a drive shaft inserted in said shaftbore such that an annular space is formed between an inner peripheralsurface of said shaft bore and said drive shaft, said drive shaft beingcoupled to said wheel hub via a reduction gear mechanism and a clutchmechanism; a hydraulic motor attached to said wheel mounting body andhaving an output side coupled to said drive shaft; a braking mechanismmounted between said wheel hub and said wheel mounting body, whereinsaid annular space communicates with a lubricant oil inlet and aperipheral port via individual lubricable portions, and a lubricant oilis supplied from said lubricant oil inlet and is discharged from saidperipheral port; and a discharging conduit connected to said peripheralport.
 2. The lubricating structure as claimed in claim 1, furthercomprising:a cover attached to said hydraulic motor, said cover havingsaid lubricant oil inlet formed therein; and a gear containing portionprovided between said lubricant oil inlet and said annular space formedbetween said drive shaft and said shaft bore.
 3. The lubricatingstructure as claimed in claim 1, further comprising a bearing disposedbetween said wheel hub and said wheel mounting body, wherein saidbearing is located between said annular space and said peripheral port.4. The lubricating structure as claimed in claim 1, wherein said brakingmechanism is located between said annular space and said peripheralport.
 5. A lubricating structure for a wheel driving apparatus, saidlubricating structure comprising:a wheel mounting body rotatablysupporting a wheel hub on which a tire can be mounted, said wheelmounting body defining a shaft bore therein; a first oil aperture formedin a central side of said wheel mounting body; a second oil apertureformed in said wheel hub; a drive shaft engageably inserted in saidshaft bore, said drive shaft being coupled to said wheel hub via areduction gear mechanism and a clutch mechanism having a pressurereceiving chamber; a hydraulic motor attached to said wheel mountingbody and having an output side coupled to said drive shaft; and abraking mechanism mounted between said wheel hub and said wheel mountingbody, wherein said first oil aperture communicates with said second oilaperture via a rotary sealing portion, said second oil aperturecommunicates with said pressure receiving chamber of said clutchmechanism, said rotary sealing portion communicates with a peripheralport via individual lubricable portions, and leakage oil from saidrotary sealing portion is discharged from said port while a clutchingpurpose pressurized lubricant oil is supplied from said first oilaperture.
 6. The lubricating structure as claimed in claim 2, furthercomprising a bearing disposed between said wheel hub and said wheelmounting body, wherein said bearing is located between said rotarysealing portion and said port.
 7. The lubricating structure as claimedin claim 5, wherein said breaking mechanism is located between saidrotary sealing portion and said port.
 8. The lubricating structure asclaimed in claim 5, further comprising a discharging conduit connectedto said port.
 9. A lubricating structure for a wheel driving apparatus,said lubricating structure comprising:a wheel mounting body rotatablysupporting a wheel hub on which a tire can be mounted, said wheelmounting body defining a shaft bore therein; a first oil aperture formedin a central side of said wheel mounting body; a second oil apertureformed in said wheel hub; a drive shaft inserted in said shaft bore soas to define an annular space between an inner peripheral surface ofsaid shaft bore and said drive shaft, said drive shaft being coupled tosaid wheel hub via a reduction gear mechanism and a clutch mechanismhaving a pressure receiving chamber; a hydraulic motor attached to saidwheel mounting body and having an output side coupled to said driveshaft; and a braking mechanism mounted between said wheel hub and saidwheel mounting body, wherein said annular space communicates with alubricant oil inlet and a peripheral port via individual lubricableportions, a lubricant oil is supplied from said lubricant oil inlet andis discharged from said peripheral port, said first oil aperturecommunicates via a rotary sealing portion with said second oil aperture,said second oil aperture communicates with said pressure receivingchamber of said clutch mechanism, said rotary sealing portioncommunicates with said peripheral port via individual lubricableportions, and leakage oil from said rotary sealing portion is dischargedfrom said peripheral port while a clutching purpose pressurizedlubricant oil is supplied from said first oil aperture.
 10. Thelubricating structure as claimed in claim 9, further comprising abearing disposed between said wheel hub and said wheel mounting body,wherein said bearing is located between said rotary sealing portion andsaid port.
 11. The lubricating structure as claimed in claim 9, whereinsaid braking mechanism is located between said rotary sealing portionand said port.
 12. The lubricating structure as claimed in claim 9,further comprising a discharging conduit connected to said port.